The rear side window of many passenger cars is divided by a window bar into an approximately triangular area and a rectangular area. The shading of the rectangular area with the help of a shade is generally straightforward. However, shading the triangular area can be more difficult.
Typically, a recess is present in the door below the triangular area. This recess is produced by the wheel housing in the car body. As a result of the recess, the available space inside the body of the door below the triangular area is very limited. As a rule, it is not possible to extend the guide rail for the triangular window shade a sufficient distance in the direction towards the tip of the triangular area. The guide rail must end a certain distance before the tip. As a result, the drive element that connects the tip of the shade sheet to the slide in the guide rail must be either movable or it must perform, together with the slide, a pivoting motion during the course of the deployment movement. In each case, in the retracted state, the catch that produces the coupling between the shade sheet and the slide below the bottom edge of the window must be parallel to the window post when the shade is retracted, so that it is visible as little as possible.
To force the pivoting motion, it is known to use two guide rails that enclose an angle, where the distance between the guide rails decreases towards the back of the vehicle (i.e., in the direction of the tip of the triangular window). One end of the guide slide runs in one guide groove and the other end of the guide slide extends in the other guide groove. However, because the two grooves come closer to each other, the slide performs the desired pivoting motion at the end of the window. However, this arrangement requires considerable space in the vertical direction. Moreover, the guide rails in which the slide runs are also quire expensive.
A side window shade is disclosed in EP 1 676 735 A2 in which only one guide rail below the bottom edge of the window is used. Over the entire length, the guide rail has a curved profile that is approximately parallel to the upper edge of the small window in such a way that both radii of curvature have the same center. As a result, a relatively deep pocket is formed in the vicinity of the back edge of the window, because the guide rail is set backwards by a very large distance at that location as compared to the bottom edge of the window. Deep pockets that open upwards are very undesirable in a motor vehicle. It is easy for parts to fall in them, which can then not be removed at all or only with considerable difficulty. This applies particularly to the back area of the motor vehicle where the passengers are usually children.